A soldier from the M23 rebel group looks on as thousands of Congolese people listen during an M23 rally, in Goma, eastern Congo, Wednesday.

UNITED NATIONS — The Rwandan military is commanding and supporting the rebel force that overtook a major city in eastern Congo this week, a United Nations report released Wednesday said. The report also said Uganda is providing more subtle but nonetheless decisive backing support to the M23 rebels.

The report’s release, just one day after the violent takeover of Goma, is sure to increase pressure on the international community to confront the two eastern African countries over their role in neighboring Congo’s conflict. Both Rwanda and Uganda have repeatedly denied supporting the M23 movement and have faced little international criticism over the allegations.

The highly anticipated report from the U.N. Group of Experts said both Rwanda and Uganda have “cooperated to support the creation and expansion of the political branch of M23 and have consistently advocated on behalf of the rebels. M23 and its allies include six sanctioned individuals, some of whom reside in or regularly travel to Rwanda and Uganda.”

The document said that Rwanda is funneling weapons and providing direct troops reinforcements to the M23 rebels. It is facilitating recruitment and encouraging desertions from the Congolese armed forces.

“The de facto chain of command of M23 includes (rebel leader) Gen. Bosco Ntaganda and culminates with the Minister of Defence of Rwanda, Gen. James Kabarebe,” the report said.

The report puts the U.N. in an uncomfortable position. Rwanda has been elected by the U.N. General Assembly to serve a two-year position on the 15-member Security Council beginning in January, which will complicate efforts by the council to come to grips with the country’s intervention in Congo.

The Security Council voted unanimously Tuesday to impose travel bans, assets freezes and other sanctions on the leaders of M23 and called for an end to external support for the rebellion, but without naming Rwanda or Uganda.

Rwanda’s representative spoke to the council after the vote to deny that his country is involved in the Congolese rebellion. Uganda has previously denied involvement and said it would pull its troops out of U.N. peacekeeping operations if it was named in the report.

Timothy Longman, director of Boston University’s African Studies Center, said the U.S. and other countries have been reluctant to confront Rwanda out of lingering sympathy for its 1994 genocide and because the country is considered a successful model for development. He said Rwanda has become a key international player under President Paul Kagame, including supplying troops for the African Union mission in Darfur.

“The international community needs to stop pretending like Kagame is a benign leader and realize that the green light given to his unacceptable behavior in the past is allowing him to get away with literally murder,” said Longman, a former director of the Human Rights Watch office in Rwanda.

The U.S. suspended its military aid — albeit only $200,000 — to Rwanda after parts of the U.N. preliminary report were leaked last month. Other European countries followed suit, suspending humanitarian aid to Rwanda.

The U.S. Mission to the U.N. did not immediately return a request for comment Wednesday.

The M23 movement, which was born in April when hundreds of troops defected from the Congolese armed forces, now has some 1,250 troops, according to the report.

Thousands of Congolese soldiers and policemen defected to the M23 rebels Wednesday as rebel leaders vowed to take control of all Congo, including the capital, Kinshasa.

The U.N. report accuses the M23 commanders of recruiting hundreds of young boys and girls as soldiers and ordering the extrajudicial executions of dozens of recruits and prisoners of war.

The document cites members of the Congolese army, current and former M23 members and former members of the Rwanda military who attested to Rwandan weapons deliveries to the rebels and the deployment of Rwandan troops to help consolidate rebel control over territory. It said senior Ugandan officials have also provided direct troop reinforcement, weapons delivery and technical and political assistance to the rebels.

Rwandan support was critical to the M23 capture of four eastern Congo towns in July, the report said. The Rwandan army deployed more than 2,000 soldiers to help seize Bunagana, and Rwandan commanders provided machine guns, anti-tank and anti-aircraft launchers ahead of the attack, it said.

Prior to the July assaults, Ntaganda and other rebel commanders flew to Rwanda to meet with Kabarebe, the Rwandan defense minister, the report said.

The report said that Rwandan soldiers and M23 rebels communicate through commercial radio sets that the rebels obtained while in the Congolese armed forces. The Congolese military has thus been able to intercept several communications between Rwandan soldiers and M23 combatants, the experts said. One member of the U.N. Group of Experts witnessed an M23 commander communicating by radio with Rwandan troops for reinforcements.

Earlier Wednesday, the U.N.’s special representative for Congo said the 19,000-strong U.N. peacekeeping force there is being stretched thin by multiple rebel militias in the eastern part of the country, including Goma.

Roger Meece made the assessment in a live videoconference linkup to the Security Council from Kinshasa.

The council is assessing the performance of the MONUSCO peacekeeping force after 1,500 of its troops stood by Tuesday and let M23 rebels take Goma without resistance.

U.N. helicopters over the weekend fired hundreds of rockets at the rebels in a bid to slow their advance on the city of 1 million.

But U.N. officials say the U.N. force commander in Goma ordered the peacekeepers not to shoot Tuesday in order to avoid provoking a major firefight in the city after Congolese troops retreated.

Meece said the M23 rebels were “well provisioned,” uniformed and supplied with weapons, including night-vision goggles, which clearly came from some outside party.